1T-phase MoS ₂ quantum dots as a superior co-catalyst to Pt decorated on carbon nitride nanorods for photocatalytic hydrogen evolution from water

Abstract

1T-MoS ₂ QDs exceed the performance of Pt as co-catalysts in assisting photocatalytic H ₂ evolution upon forming a heterostructure with C ₃N ₄ nanorods.

Abstract

Molybdenum disulfide (MoS ₂) has been confirmed to be a promising non-precious-metal co-catalyst for photocatalytic hydrogen (H ₂) evolution; however, its low-density of active sites and poor electron transfer efficiency have essentially limited its photocatalytic properties. Here we report that 1T-MoS ₂ quantum dots (QDs) can exceed the performance of noble metals like Pt as co-catalysts in assisting photocatalytic H ₂ evolution upon forming a heterostructure with C ₃N ₄ nanorods (denoted as 1T-MoS ₂@C ₃N ₄ NRs). The presence of 1T-MoS ₂ QDs is found to improve light harvesting, enhance electronic conductivity as well as boost the density of active sites, resulting in an excellent light absorption range up to the near-infrared (NIR) region and a highly efficient spatial charge separation and transfer process. As a result, the optimized 1T-MoS ₂@C ₃N ₄ NR composite (5.0 wt%) exhibits an extraordinary photocatalytic H ₂ production rate of 565 μmol h ⁻¹ g ⁻¹ under simulated solar light irradiation, obviously higher than that of noble metal Pt loaded C ₃N ₄ NRs (318 μmol h ⁻¹ g ⁻¹). Moreover, the 1T-MoS ₂@C ₃N ₄ NR composites exhibit good stability in the cyclic runs for photocatalytic H ₂ production. This study indicates that the highly active MoS ₂ as a co-catalyst is highly promising as a substitute for Pt for photocatalytic H ₂ evolution.